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10 Rulison Institutional Control Site of the second nuclear gas stimulation experiment in the United States. One 43 kiloton nuclear explosive was detonated in this well, 8,326 feet below the surface on September 10, 1969. No excavation, drilling, and/or removal of subsurface materials below a depth of 6,000 feet is permitted in Lot 11, NE ¼ SW ¼, of section 25, Township 7 South, Range 95 West, 6th Principal Meridian, Garfield County, Colorado, without U.S. Government permission. U.S. Energy Research and Development Administration September 1976

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11 Rulison COGCC Notification Zone and Hearing Boundary In 1997, the Colorado Oil and Gas Conservation Commission (COGCC) established a three-mile radius around surface ground zero, based on the fact that no existing gas well was closer than three miles. As part of this informal policy, DOE receives notification when COGCC receives an Application for Permit to Drill (APD) within three miles of surface ground zero. In 2004, COGCC formally established a half-mile radius, with the provision that any APD for a well within a half-mile of the surface ground zero would require a full COGCC hearing prior to issuance.

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15 Rio Blanco Institutional Control Site of the third nuclear gas stimulation experiment in the United States of America. Three 30 kiloton nuclear explosives were detonated in this well at 5,838 feet, 6,230 feet, and 6,689 feet below the surface on May 17, 1973. No excavation, drilling, and/or removal of subsurface materials to a true vertical depth of 1,500 feet is permitted within a radius of 100 feet of this surface location, nor any similar excavation, drilling, and/or removal of subsurface materials between the true vertical depths of 1,500 feet and 7,500 feet is permitted within a 600 foot radius of this surface location in the NW quarter, section 14, Township 3 South, Range 98 West, 6th Principal Meridian, Rio Blanco County, Colorado, without U.S. Government permission. U.S. Energy Research and Development Administration September 1976

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17 Summary Two underground nuclear tests were conducted in Colorado to stimulate gas production. No technically feasible way to remove radioactive contamination in nuclear cavities. Potential for contaminants to migrate to gas-producing channels if drilling or hydraulic fracturing penetrates contaminant zone surrounding the nuclear cavities. DOE will continue to maintain boundaries that protect human health and the environment.